“Iron is built into the enzymes that do most of the chemical heavy lifting in our bodies, where it helps us to detoxify poisons and to convert sugars into energy. Iron-poor diets and other iron deficiencies are the most common cause of anemia, a lack of red blood cells that can cause fatigue, shortness of breath, and even heart failure…Without enough iron our immune system functions poorly, the skin gets pail, and people can feel confused, dizzy, cold, and extremely fatigue” (1)
This excerpt clearly shows us that iron is essential to the human body, and without it we cannot function. Iron is a nutrient that performs many different body functions. Most of the iron in the body is found in two different proteins; hemoglobin in the red cells and myoglobin in muscle cells. Iron functions by accepting oxygen in hemoglobin and then releasing oxygen throughout the body. (2) Iron found in the muscle protein, myoglobin, uptakes oxygen from hemoglobin and diffuses the oxygen through the muscle cells. (2) This can be connected back to what we have learned in class about the circulatory and respiratory system, because iron plays a key role in both of these mechanisms, functioning as the main source in the formation of hemoglobin, and helping in transport oxygen from the lungs to the body. Moreover, iron holds an important function in our digestive systems, because iron is absorbed from the food sourced in the small intestine. More specifically, iron is absorbed in the duodenum by enterocytes of the duodenal lining. Iron can be absorbed as part of the heme protein or in it’s ferrous Fe2+ state. (2) The intestinal lining cells can either store the iron as ferritin or the cell can maneuver it into the body via the protein, ferroportin.(2) When the body demands iron, it is packaged into transferrin, which is a transport protein that is carried in the blood.
Moreover, we had discussed the cause of anemia and its effects on the human body in class. We learned that insufficient amounts of iron in the body could lead to the development of Iron deficiency anemia. If there is a very limited supply of iron available, then so is the supply of hemoglobin, which affects the red blood cells production. This short supply of hemoglobin and red blood cells causes anemia, which affects the body as whole, because the oxygen transportation to the cells and tissues of the body is greatly decreased. Iron deficiency anemia causes fatigueness, shortness of breath, dizziness, concentration problems, and a weakened immune system. (1)
There are many causes of Iron deficiency Anemia, the main ones being the intake of iron-poor foods, blood loss, and the inability to absorb iron. (1) Blood loss from the gastrointestinal tract is one of the main causes of anemia in both females and males. (1) For example, females experience blood loss monthly during their menstrual cycles. This is one of the reasons why females have a high rate of getting anemic then males do. Below is a simplistic chart that shows demographic, dietary, and social, and physical factors that put people at risk of developing Iron deficiency anemia.
Even though iron holds many functions that help our bodies, it has the ability to have damaging affects to our body as well. Taking in excess amounts of iron can cause damage to the brain as well as the heart, which can lead to a heart attack or a stroke (1) Hemochromatosis is heredity disease that is characterized by an increased absorption of iron and the accumulation of it in the body tissues (3) This leaves the body helpless to the point where it has no “natural” way of getting rid of its excess iron, which in turn causes damage to the body tissues. It’s really interesting to see how vital iron is to our bodies, the fact that we can’t live without it, but at the same time, we can’t have too much of it. We have to be really careful in taking a sufficient supply of iron for our health, but at the same time not to overdose on it either, since it can have damaging effects, and hurt us in the long run. This excerpt connects back to one of the biology themes of regulation. Iron regulation throughout our body is essential to our well-being, because iron metabolism is important to the formation and proper of red blood cells, something that we cannot live without.
Works Cited
(1) "Iron Deficiency Anemia: EMedicine Hematology." EMedicine - Medical Reference. Web. 28 May 2010. <http://emedicine.medscape.com/article/202333- overview>.
(2) "Iron - Importance for Health." Healthy Vitamin Choice: Quality Information, People Who Care. Web. 28 May 2010. <http://www.healthy-vitamin-choice.com/iron.html>.
(3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with Jonathan Prince. NY: HarperCollins, 2007. Print
POST 2:
"Diabetes is all about the body's relationship to sugar, specifically the blood sugar known as glucose. Glucose is produced when the body breaks down carbohydrates in the food we eat. It's essential to survival--it provides fuel for the brain; it's required to manufacture proteins; it's what we use to make energy when we need it. With the help of insulin, a hormone made by the pancrease, glucose is stored in your liver, muscles, and fat cells (think of them as your own internal OPEC) waiting to be converted to fuel as necessary" (3)
This excerpt connects to the theme of regulation of biology, in this case the regulation of blood glucose. We spent a lot of time in biology class talking about the hormones glucagon and insulin, which are secreted in response to the blood sugar levels of the body. Insulin and glucagon are both secreted from the pancreas, and are referred to as pancreatic endocrine hormones. Insulin is secreted by beta cells of the pancreas in response to high blood glucose levels. (1) Glucagon on the other hand is secreted by the alpha cells in response to low blood sugar levels. (1) Below is a picture that simply illustrates both insulin and glucagon in the body system.
Insulin affects many different cells, including muscle, red blood cells, and fat cells. When insulin is secreted, these different cells absorb glucose out of the blood, thus lowering the high blood sugar levels to a normal level. (1) Glucagon, when secreted, affects the liver, because it makes the liver release its stored glucose into the blood stream, thus causing the blood sugar level to increase. (1)
Moroever, this excerpt talks of diabetes, something that we talked about in class. Diabetes is a disease that affects over 150 million people in the world! The amount of people affected by diabetes is greatly increasing day by day.
Diabetes is a condition that prevents your body from turning the food that you consume into energy. Diabetes developes as a result of either the body not producing insulin, or as a result of body cells not properly responding to insulin that is produced. This disables the body cells to absorb the glucose and thus turn it into energy. If the body cells can’t absorb the glucose, then the glucose amount adds up in the blood, causing high levels of sugar in the bloodstream. This can lead to many internal problems. Over time, the high glucose level in the blood causes damage to nerve and blood vessels, and can lead to serious complications like hear disease and stroke, which are the leading causes of deaths of diabetic people. (2)
I know that diabetes is a serious problem today because so many people are diagnosed with it each day. I personally know so many people with diabetes. Diabetes runs in my family and I know how much influence it has on ones’ life. It is interesting to see how diabetes causes other disorders like heart disease and stroke, which are the death factors of many people today. This excerpt connects diabetes with the blood sugar levels in the body, something that I had learned in depth in biology class. But even for people that have no background of this, it wouldn’t be difficult for them to understand the concept of blood level regulation in the body, because it’s a quite simple cycle. Again the diagram above is a great illustration of how this works. Works Cited
(1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Information about Diabetes : What Is Diabetes? Web. 02 June 2010. <http://www.informationaboutdiabetes.com/>.
(3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with Jonathan Prince. NY: HarperCollins, 2007. Print
POST # 3
"As everybody knows, skin color changes, to some extent, in response to sun exposure. The trigger for that response is pituitary gland. Under natural circumstances, almost as soon as soon as you are exposed to the sun, your pituitary gland produces hormones that act as boosters for you melanocytes, and your melanocytes start producing melanin on overdrive. The pituitary gland gets its information form the optic nerve--when the optic nerve senses sunlight, it signals the pituitary glad to kick-start the melanocytes. Guess what happens when you're wearing sunglasses? Much less sunlight reaches the optical nerves, much less warning is sent to the pituitary glad, much less melanocyte-stimulating hormone is released, much less melanin is produced--and much more sunburn results." (3)
This excerpt correlates with the hormones from the pituitary glands, something that we covered a great deal on in Biology class, and connects to the theme of regulation. We learned that the pituitary gland includes the posterior pituitary and anterior pituitary, and secretes many different types of hormones. The pituitary gland produces hormones like oxytocin, antiduiretic hormone (ADH), prolactin (PRL), growth hormone (GH), Follicle-stimulating hormone (FSH), thyroid-stimulating hormone (ACTH), luteinizing hormone (LH), and many others. (1) These hormones affect the body in numerous ways. For example, ADH promoted the retention of water by kidneys, the growth hormone stimulates body growth as well as metabolic functions, and the LH stimulates ovaries and testes. Overall, this excerpt covers over the endocrine system, and is connected to the "regulation" them of biology, because the endocrine system uses hormones to regulate cellular functions.
This excerpt talks of the melonocyte-stimulating hormone (MSH), a peptide hormone secreted by the anterior pituitary gland that acts on neurons in the brain. (1) MSH stimulates the production and release of melanin by melanocytes in skin as well as hair. (2) MSH is also produced by neurons in the arcuate nucleus of the hypothalamus, and is released into the brain, which also has effects one’s appetite. Melanin, a pigment, is what determines the skin color of a person. It is found in one’s hair (gives the hair color), the pigmented tissue under the iris of the eye (giving the iris it’s color), and in pigmented neurons within the brain system. (2) The basic concept is that those that have darker skin have more melanin than those that have lighter skin, who have very little pigmentation.
At the end of this excerpt, Dr. Moalem states how wearing sunglasses were bad for you because it hurts your skin. “If you’re reading this on the beach with your Ray-Bans on, do your skin a favor—take them off” (3) I was really surprise about what he said. I mean in a way what he said did make sense, about the pituitary gland reading off of the optic nerve, and because the optic nerve was getting less exposure to the UV light, it halted the secretion of melanocyte-stimulating hormone, which in turn would cause sunburn not tanning of one’s skin. But i still disagreed with his point because I always thought that wearing sunglasses was actually good for your eyes not the other way around. In addition, I find it hard to believe that just by blocking the UV light to your eyes with sunglasses could affect the skin of your overall body. Many opthomalogists, including my own, recommend wearing glasses to protect the skin in the eye area from premature signs of aging due to the UV rays and sun damage . (3) Some people think that by wearing sunglasses, the vitamin D absorption from the sun is halted, but can’t you absorb vitamin D through your skin? I feel that he should have added more to his statement, then blatantly saying how sunglasses were bad for you. Overall, his last statement is giving people bad advice, because he doesn’t even mention the damages that could occur to one’s eyes by not wearing sunglasses. I personally feel that sunglasses are a good way to protect your eyes from the sun damage, and feel that wearing them won’t really impact my skin, so I’m definitely sticking to my Ray-Bans!
Works Cited: (1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) "Melanocyte-stimulating Hormone (MSH)." The Worlds of David Darling. Web. 06 June 2010.
<http://www.daviddarling.info/encyclopedia/M/melanocyte-stimulating_hormone.html>. (3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print
POST #4
(pg 187) "As we've discussed, your body has multiple lines of cancer defenses. There are specific genes responsible for tumor suppression. There are genes responsible for creating specialized cancer hunters programmed to seek and destroy cancer cells. There are genes responsible for repairing the genes that fight cancer. Cells even have a mechanisms to commit a kind of hara-hiri. Apoptosis, or programmed cell death, occurs when a cell detects a problem, and 'convince' the dangerous cell to kill itself. And on top of that there's the Hayflick limit." (2)
This excerpt talks about Cancer and the type of genes that are associated with and it’s mechanisms, something we greatly covered in our Biology class. Cancer is a set of diseases in which abnormal cells divide uncontrollably and capable of invading other tissues, meaning that it can spread to other parts of the body through the blood and lymph systems. (1) Basically, cancer results from genetic changes that affect cell cycle control. The gene regulation systems that go wrong during cancer are actually the same systems that play important roles in embryonic development, the immune response, and many other biological processes. (1)
The genes that normally regulate cell growth and division during the cell cycle includes genes for growth factors, their receptors, and the intracellular molecules of signaling pathways. Mutations that can affect these genes in the somatic cells can lead up to cancer. (1) Many of these mutations are the result from environmental influences, such as chemical carcinogens, X-rays, and specific viruses.
Cancer causing genes are called oncogens, which are in certain retroviruses. (3) On the hand, proto-oncogenes are the normal cellular genes, which code for proteins that stimulate normal cell growth and division. Moreover, cells contain genes whose normal products inhibit cell division; these are called tumor-suppressor genes. (3) The tumor-suppressor genes encode proteins that help prevent uncontrollable cell growth. Apoptosis is the process of a programmed cell death. (3) So apoptosis may occur in cases during a tumor development, and when it functions properly, the body can use the process of apoptosis to rid itself of cancer cells. A tumor suppression gene helps regulate the cell cycle, and plays a key role in making sure that the damaged cells are destroyed by apoptosis.
This diagram clearly shows the programmed cell death (apoptosis). I must admit, that when Dr. Moalem mentioned the “Hayflick limit,” I had no idea what he was talking about. After researching it on the internet, I found it to be quite interesting. The Hayflick limit is the number of times a normal cell can divide before it stops, mostly due to the fact that the telemeres reach a “critical strength.” (3) This was discovered by Leonard Hayflick in 1961, where he demonstrated that a population of normal human fetal cells in a culture divide between 40 to 60 times. (3) He then explained, that after this, it enters the “senescence” phase, and each mitosis shortens the telomers on the DNA of the cell. (3) And the shortening of the telomeres in our bodies eventually blocks the cell division, and this also relates with aging. Because of this mechanism, it is possible to prevent the development of caner. Overall, this was an interesting passage to pick, because even though I had thought I knowledge of some of this stuff, I learned a lot through the process. It was really interesting to learn that our bodies hold so many genes that could help us prevent cancer. I know that today apoptosis therapy is being looked into for helping get rid of cancer. Overall, this excerpt relates to the biology theme of cell regulation, because you see that there are genes in the body that help regulate the cell cycle, and can even alter the way it divides.
Works Cited: (1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print
(3) "Research Apoptosis or Programmed Cell Death and Cancer." Genentech BioOncology Cancer Therapy Research. Web. 11 June 2010. <http://www.biooncology.com/research/apoptosis/index.html>.
POST # 5
pg 188
" Stem cells are "undifferentiated" cells--in other words, they can divide into many different kinds of cells. A B-cell that makes your antibodies can only divide into another B-cell, and a kin cell can only produce another skin cell. Stem cells can produce many types of cells--the mother of all stem cells, of course, is the single cell that started off in your mother" (2)
Stem cells are unspecialized cells that can both reproduce itself indefinitely and, under proper conditions, differentiate into specialized cells of one or more types.(1) Many early embryos contain totipotent stem cells, which are able to give rise to differentiated cells of any type. (1) Stem cells can be isolated from early embryos at the blastula stage. These embryonic stem cells, when in culture, can reproduce indefinitely into various "specialized" cells, including eggs and sperms. This however, all depends on the culture conditions.(1) The adult stem cells also holds a variety of stem cells. These stem cells serve to to replace non-reproducing specialized cells when needed. Adult stems are called pluripotent, which means that it is able to give rise to multiple cell types.(1) Stem cells in the bone marrow give rise to many different kinds of blood cells.
Scientists have recently discovered that the adult brain contains stem cells that continue to produce certain kinds of nerve cells there. Today scientists are learning to identify and isolate stem cells from different tissues, and want to grow them in culture. Scientists have learned that with proper culture and culture conditions, the cultured stem cells from adults can differentiate into many different types of specialized cells, something that we're really looking into today.(2) The Research with embryonic or adult stem cells is giving us valuable information about differentiation and has an enormous potential for medical purposes. (2) Our ultimate goal is to provide cells that can repair damages or diseases organs, something that will help us greatly and save lives.Embryonic stem cells are currently mostly obtained from embryos donated by patients undergoing infertility treatment. With the cloning of the human embryos to the blastocyst stage, there is great potential that scientists will these as a source of embryonic stem cells in the future.(2) This process is called "therapeutic cloning," in other words, this is the process that has one aim; cloning to produce embryonic stem cells to treat disease.(2)
This excerpt gives an intro to stem cells, something that we majorly discussed in biology class. The topic of stem cells is quite interesting and a hot topic today, mainly because so many people hold such different opinions on it. Many people think that cloning is unethical, because they feel that they shouldn't have the "power" to create or destroy embryos. Others believe that this is the only way for us to advance further and therapeutic cloning really might help us in treating many diseases. I can understand both point of views though. I personally don't hold one opinion over the other but falls right in between. I personally feel that stem cell research does have great potential for us in the future, and it will really help with the treating of many diseases. But i feel that our source of stem cells should be limited. I feel that if we want to use the stem cells derived from adult human beings for research, than that is totally fine, because it is not ethically wrong. But I don't agree with the fact that scientists think it's okay to use stem cells derived from human embryos, because that is morally wrong. However, scientists are going to do whatever they can to advance in science.
Works Cited: (1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print
“Iron is built into the enzymes that do most of the chemical heavy lifting in our bodies, where it helps us to detoxify poisons and to convert sugars into energy. Iron-poor diets and other iron deficiencies are the most common cause of anemia, a lack of red blood cells that can cause fatigue, shortness of breath, and even heart failure…Without enough iron our immune system functions poorly, the skin gets pail, and people can feel confused, dizzy, cold, and extremely fatigue” (1)
This excerpt clearly shows us that iron is essential to the human body, and without it we cannot function. Iron is a nutrient that performs many different body functions. Most of the iron in the body is found in two different proteins; hemoglobin in the red cells and myoglobin in muscle cells. Iron functions by accepting oxygen in hemoglobin and then releasing oxygen throughout the body. (2) Iron found in the muscle protein, myoglobin, uptakes oxygen from hemoglobin and diffuses the oxygen through the muscle cells. (2) This can be connected back to what we have learned in class about the circulatory and respiratory system, because iron plays a key role in both of these mechanisms, functioning as the main source in the formation of hemoglobin, and helping in transport oxygen from the lungs to the body. Moreover, iron holds an important function in our digestive systems, because iron is absorbed from the food sourced in the small intestine. More specifically, iron is absorbed in the duodenum by enterocytes of the duodenal lining. Iron can be absorbed as part of the heme protein or in it’s ferrous Fe2+ state. (2) The intestinal lining cells can either store the iron as ferritin or the cell can maneuver it into the body via the protein, ferroportin.(2) When the body demands iron, it is packaged into transferrin, which is a transport protein that is carried in the blood.
Moreover, we had discussed the cause of anemia and its effects on the human body in class. We learned that insufficient amounts of iron in the body could lead to the development of Iron deficiency anemia. If there is a very limited supply of iron available, then so is the supply of hemoglobin, which affects the red blood cells production. This short supply of hemoglobin and red blood cells causes anemia, which affects the body as whole, because the oxygen transportation to the cells and tissues of the body is greatly decreased. Iron deficiency anemia causes fatigueness, shortness of breath, dizziness, concentration problems, and a weakened immune system. (1)
There are many causes of Iron deficiency Anemia, the main ones being the intake of iron-poor foods, blood loss, and the inability to absorb iron. (1) Blood loss from the gastrointestinal tract is one of the main causes of anemia in both females and males. (1) For example, females experience blood loss monthly during their menstrual cycles. This is one of the reasons why females have a high rate of getting anemic then males do. Below is a simplistic chart that shows demographic, dietary, and social, and physical factors that put people at risk of developing Iron deficiency anemia.
Even though iron holds many functions that help our bodies, it has the ability to have damaging affects to our body as well. Taking in excess amounts of iron can cause damage to the brain as well as the heart, which can lead to a heart attack or a stroke (1) Hemochromatosis is heredity disease that is characterized by an increased absorption of iron and the accumulation of it in the body tissues (3) This leaves the body helpless to the point where it has no “natural” way of getting rid of its excess iron, which in turn causes damage to the body tissues. It’s really interesting to see how vital iron is to our bodies, the fact that we can’t live without it, but at the same time, we can’t have too much of it. We have to be really careful in taking a sufficient supply of iron for our health, but at the same time not to overdose on it either, since it can have damaging effects, and hurt us in the long run. This excerpt connects back to one of the biology themes of regulation. Iron regulation throughout our body is essential to our well-being, because iron metabolism is important to the formation and proper of red blood cells, something that we cannot live without.
Works Cited
(1) "Iron Deficiency Anemia: EMedicine Hematology." EMedicine - Medical Reference. Web. 28 May 2010. <http://emedicine.medscape.com/article/202333- overview>.
(2) "Iron - Importance for Health." Healthy Vitamin Choice: Quality Information, People Who Care. Web. 28 May 2010. <http://www.healthy-vitamin-choice.com/iron.html>.
(3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with Jonathan Prince. NY: HarperCollins, 2007. Print
POST 2:
"Diabetes is all about the body's relationship to sugar, specifically the blood sugar known as glucose. Glucose is produced when the body breaks down carbohydrates in the food we eat. It's essential to survival--it provides fuel for the brain; it's required to manufacture proteins; it's what we use to make energy when we need it. With the help of insulin, a hormone made by the pancrease, glucose is stored in your liver, muscles, and fat cells (think of them as your own internal OPEC) waiting to be converted to fuel as necessary" (3)
This excerpt connects to the theme of regulation of biology, in this case the regulation of blood glucose. We spent a lot of time in biology class talking about the hormones glucagon and insulin, which are secreted in response to the blood sugar levels of the body. Insulin and glucagon are both secreted from the pancreas, and are referred to as pancreatic endocrine hormones. Insulin is secreted by beta cells of the pancreas in response to high blood glucose levels. (1) Glucagon on the other hand is secreted by the alpha cells in response to low blood sugar levels. (1) Below is a picture that simply illustrates both insulin and glucagon in the body system.
Insulin affects many different cells, including muscle, red blood cells, and fat cells. When insulin is secreted, these different cells absorb glucose out of the blood, thus lowering the high blood sugar levels to a normal level. (1) Glucagon, when secreted, affects the liver, because it makes the liver release its stored glucose into the blood stream, thus causing the blood sugar level to increase. (1)
Moroever, this excerpt talks of diabetes, something that we talked about in class. Diabetes is a disease that affects over 150 million people in the world! The amount of people affected by diabetes is greatly increasing day by day.
Diabetes is a condition that prevents your body from turning the food that you consume into energy. Diabetes developes as a result of either the body not producing insulin, or as a result of body cells not properly responding to insulin that is produced. This disables the body cells to absorb the glucose and thus turn it into energy. If the body cells can’t absorb the glucose, then the glucose amount adds up in the blood, causing high levels of sugar in the bloodstream. This can lead to many internal problems. Over time, the high glucose level in the blood causes damage to nerve and blood vessels, and can lead to serious complications like hear disease and stroke, which are the leading causes of deaths of diabetic people. (2)
I know that diabetes is a serious problem today because so many people are diagnosed with it each day. I personally know so many people with diabetes. Diabetes runs in my family and I know how much influence it has on ones’ life. It is interesting to see how diabetes causes other disorders like heart disease and stroke, which are the death factors of many people today. This excerpt connects diabetes with the blood sugar levels in the body, something that I had learned in depth in biology class. But even for people that have no background of this, it wouldn’t be difficult for them to understand the concept of blood level regulation in the body, because it’s a quite simple cycle. Again the diagram above is a great illustration of how this works.
Works Cited
(1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Information about Diabetes : What Is Diabetes? Web. 02 June 2010. <http://www.informationaboutdiabetes.com/>.
(3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with Jonathan Prince. NY: HarperCollins, 2007. Print
POST # 3
"As everybody knows, skin color changes, to some extent, in response to sun exposure. The trigger for that response is pituitary gland. Under natural circumstances, almost as soon as soon as you are exposed to the sun, your pituitary gland produces hormones that act as boosters for you melanocytes, and your melanocytes start producing melanin on overdrive. The pituitary gland gets its information form the optic nerve--when the optic nerve senses sunlight, it signals the pituitary glad to kick-start the melanocytes. Guess what happens when you're wearing sunglasses? Much less sunlight reaches the optical nerves, much less warning is sent to the pituitary glad, much less melanocyte-stimulating hormone is released, much less melanin is produced--and much more sunburn results." (3)
This excerpt correlates with the hormones from the pituitary glands, something that we covered a great deal on in Biology class, and connects to the theme of regulation. We learned that the pituitary gland includes the posterior pituitary and anterior pituitary, and secretes many different types of hormones. The pituitary gland produces hormones like oxytocin, antiduiretic hormone (ADH), prolactin (PRL), growth hormone (GH), Follicle-stimulating hormone (FSH), thyroid-stimulating hormone (ACTH), luteinizing hormone (LH), and many others. (1) These hormones affect the body in numerous ways. For example, ADH promoted the retention of water by kidneys, the growth hormone stimulates body growth as well as metabolic functions, and the LH stimulates ovaries and testes. Overall, this excerpt covers over the endocrine system, and is connected to the "regulation" them of biology, because the endocrine system uses hormones to regulate cellular functions.
This excerpt talks of the melonocyte-stimulating hormone (MSH), a peptide hormone secreted by the anterior pituitary gland that acts on neurons in the brain. (1) MSH stimulates the production and release of melanin by melanocytes in skin as well as hair. (2) MSH is also produced by neurons in the arcuate nucleus of the hypothalamus, and is released into the brain, which also has effects one’s appetite. Melanin, a pigment, is what determines the skin color of a person. It is found in one’s hair (gives the hair color), the pigmented tissue under the iris of the eye (giving the iris it’s color), and in pigmented neurons within the brain system. (2) The basic concept is that those that have darker skin have more melanin than those that have lighter skin, who have very little pigmentation.
At the end of this excerpt, Dr. Moalem states how wearing sunglasses were bad for you because it hurts your skin. “If you’re reading this on the beach with your Ray-Bans on, do your skin a favor—take them off” (3) I was really surprise about what he said. I mean in a way what he said did make sense, about the pituitary gland reading off of the optic nerve, and because the optic nerve was getting less exposure to the UV light, it halted the secretion of melanocyte-stimulating hormone, which in turn would cause sunburn not tanning of one’s skin. But i still disagreed with his point because I always thought that wearing sunglasses was actually good for your eyes not the other way around. In addition, I find it hard to believe that just by blocking the UV light to your eyes with sunglasses could affect the skin of your overall body. Many opthomalogists, including my own, recommend wearing glasses to protect the skin in the eye area from premature signs of aging due to the UV rays and sun damage . (3) Some people think that by wearing sunglasses, the vitamin D absorption from the sun is halted, but can’t you absorb vitamin D through your skin? I feel that he should have added more to his statement, then blatantly saying how sunglasses were bad for you. Overall, his last statement is giving people bad advice, because he doesn’t even mention the damages that could occur to one’s eyes by not wearing sunglasses. I personally feel that sunglasses are a good way to protect your eyes from the sun damage, and feel that wearing them won’t really impact my skin, so I’m definitely sticking to my Ray-Bans!
Works Cited:
(1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) "Melanocyte-stimulating Hormone (MSH)." The Worlds of David Darling. Web. 06 June 2010.
<http://www.daviddarling.info/encyclopedia/M/melanocyte-stimulating_hormone.html>.
(3) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print
POST #4
(pg 187)
"As we've discussed, your body has multiple lines of cancer defenses. There are specific genes responsible for tumor suppression. There are genes responsible for creating specialized cancer hunters programmed to seek and destroy cancer cells. There are genes responsible for repairing the genes that fight cancer. Cells even have a mechanisms to commit a kind of hara-hiri. Apoptosis, or programmed cell death, occurs when a cell detects a problem, and 'convince' the dangerous cell to kill itself. And on top of that there's the Hayflick limit." (2)
This excerpt talks about Cancer and the type of genes that are associated with and it’s mechanisms, something we greatly covered in our Biology class. Cancer is a set of diseases in which abnormal cells divide uncontrollably and capable of invading other tissues, meaning that it can spread to other parts of the body through the blood and lymph systems. (1) Basically, cancer results from genetic changes that affect cell cycle control. The gene regulation systems that go wrong during cancer are actually the same systems that play important roles in embryonic development, the immune response, and many other biological processes. (1)
The genes that normally regulate cell growth and division during the cell cycle includes genes for growth factors, their receptors, and the intracellular molecules of signaling pathways. Mutations that can affect these genes in the somatic cells can lead up to cancer. (1) Many of these mutations are the result from environmental influences, such as chemical carcinogens, X-rays, and specific viruses.
Cancer causing genes are called oncogens, which are in certain retroviruses. (3) On the hand, proto-oncogenes are the normal cellular genes, which code for proteins that stimulate normal cell growth and division. Moreover, cells contain genes whose normal products inhibit cell division; these are called tumor-suppressor genes. (3) The tumor-suppressor genes encode proteins that help prevent uncontrollable cell growth. Apoptosis is the process of a programmed cell death. (3) So apoptosis may occur in cases during a tumor development, and when it functions properly, the body can use the process of apoptosis to rid itself of cancer cells. A tumor suppression gene helps regulate the cell cycle, and plays a key role in making sure that the damaged cells are destroyed by apoptosis.
This diagram clearly shows the programmed cell death (apoptosis).
I must admit, that when Dr. Moalem mentioned the “Hayflick limit,” I had no idea what he was talking about. After researching it on the internet, I found it to be quite interesting. The Hayflick limit is the number of times a normal cell can divide before it stops, mostly due to the fact that the telemeres reach a “critical strength.” (3) This was discovered by Leonard Hayflick in 1961, where he demonstrated that a population of normal human fetal cells in a culture divide between 40 to 60 times. (3) He then explained, that after this, it enters the “senescence” phase, and each mitosis shortens the telomers on the DNA of the cell. (3) And the shortening of the telomeres in our bodies eventually blocks the cell division, and this also relates with aging. Because of this mechanism, it is possible to prevent the development of caner.
Overall, this was an interesting passage to pick, because even though I had thought I knowledge of some of this stuff, I learned a lot through the process. It was really interesting to learn that our bodies hold so many genes that could help us prevent cancer. I know that today apoptosis therapy is being looked into for helping get rid of cancer. Overall, this excerpt relates to the biology theme of cell regulation, because you see that there are genes in the body that help regulate the cell cycle, and can even alter the way it divides.
Works Cited:
(1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print
(3) "Research Apoptosis or Programmed Cell Death and Cancer." Genentech BioOncology Cancer Therapy Research. Web. 11 June 2010. <http://www.biooncology.com/research/apoptosis/index.html>.
POST # 5
pg 188
" Stem cells are "undifferentiated" cells--in other words, they can divide into many different kinds of cells. A B-cell that makes your antibodies can only divide into another B-cell, and a kin cell can only produce another skin cell. Stem cells can produce many types of cells--the mother of all stem cells, of course, is the single cell that started off in your mother" (2)
Stem cells are unspecialized cells that can both reproduce itself indefinitely and, under proper conditions, differentiate into specialized cells of one or more types.(1) Many early embryos contain totipotent stem cells, which are able to give rise to differentiated cells of any type. (1) Stem cells can be isolated from early embryos at the blastula stage. These embryonic stem cells, when in culture, can reproduce indefinitely into various "specialized" cells, including eggs and sperms. This however, all depends on the culture conditions.(1) The adult stem cells also holds a variety of stem cells. These stem cells serve to to replace non-reproducing specialized cells when needed. Adult stems are called pluripotent, which means that it is able to give rise to multiple cell types.(1) Stem cells in the bone marrow give rise to many different kinds of blood cells.
Scientists have recently discovered that the adult brain contains stem cells that continue to produce certain kinds of nerve cells there. Today scientists are learning to identify and isolate stem cells from different tissues, and want to grow them in culture. Scientists have learned that with proper culture and culture conditions, the cultured stem cells from adults can differentiate into many different types of specialized cells, something that we're really looking into today.(2) The Research with embryonic or adult stem cells is giving us valuable information about differentiation and has an enormous potential for medical purposes. (2) Our ultimate goal is to provide cells that can repair damages or diseases organs, something that will help us greatly and save lives.Embryonic stem cells are currently mostly obtained from embryos donated by patients undergoing infertility treatment. With the cloning of the human embryos to the blastocyst stage, there is great potential that scientists will these as a source of embryonic stem cells in the future.(2) This process is called "therapeutic cloning," in other words, this is the process that has one aim; cloning to produce embryonic stem cells to treat disease.(2)
This excerpt gives an intro to stem cells, something that we majorly discussed in biology class. The topic of stem cells is quite interesting and a hot topic today, mainly because so many people hold such different opinions on it. Many people think that cloning is unethical, because they feel that they shouldn't have the "power" to create or destroy embryos. Others believe that this is the only way for us to advance further and therapeutic cloning really might help us in treating many diseases. I can understand both point of views though. I personally don't hold one opinion over the other but falls right in between. I personally feel that stem cell research does have great potential for us in the future, and it will really help with the treating of many diseases. But i feel that our source of stem cells should be limited. I feel that if we want to use the stem cells derived from adult human beings for research, than that is totally fine, because it is not ethically wrong. But I don't agree with the fact that scientists think it's okay to use stem cells derived from human embryos, because that is morally wrong. However, scientists are going to do whatever they can to advance in science.
Works Cited:
(1) Campbell, Neil A., and Jane B. Reece. Biology. San Francisco: Pearson, Benjamin Cummings, 2005. Print.
(2) Moalem, Sharon, and Jonathan Prince. Survival of the Sickest: the Surprising Connections between Disease and Longevity / Sharon Moalem with
Jonathan Prince. NY: HarperCollins, 2007. Print